(1) Field of the Invention
This invention relates to a camera and, more particularly to a camera capable of displaying the level of visual effects of a subject image which will be found in a final picture, as determined according to photographing settings.
(2) Description of the Prior Art
Recently, there has been known a camera provided with a plurality of exposure modes so that a camera operator can enjoy a variety of visual effects the camera can provide in taking pictures. Among such exposure modes are known a program mode in which photographing settings such as aperture value AV and shutter speed TV are calculated in accordance with a preset program line, aperture priority mode and shutter speed priority mode in which the aperture value and shutter speed are manually settable respectively, and a manual mode in which both the aperture value and shutter speed are manually settable. Hereafter, the program mode, aperture priority mode, shutter speed priority mode, and manual mode are respectively referred to as the P-mode, A-mode, S-mode, and M-mode.
As functions of the camera are enhanced, the operators have had to acquire more skills to obtain a final picture that he/she desires.
For instance, in taking pictures, there are cases where the operator wants not only to expose a main subject as he/she aims, but also to expose a background subject as he/she aims. It has been known to depend upon a ratio of the distance to the main subject to the distance to the background subject, focal length of the taking lens, etc. in addition to the depth of field, to determine how unsharp the background image looks in the final picture.
With the existing cameras, it has been only possible for operators skilled and experienced in photography to obtain a final picture whose background image looks as unsharp as he/she desired by taking a picture only with a fixed focal length of the taking lens.
For the purpose of visually predicting how the final picture will look, a camera of the following type has been proposed in Unexamined Japanese Patent Publication No. 1-235934. In this camera, a depth/distance value is calculated based on the distance to a main subject, focal length and aperture value of a taking lens. The depth of field impression, i.e., how much or less depth of field a final picture will provide, is estimated based on the depth/distance value: and a degree of depth of field in the final picture and that of panning are predictively displayed on a viewfinder screen.
However, the depth of field impression described in the above publication is nothing but an index quantitatively indicating at what rate the image behind the main subject becomes unsharp in the final picture and does not take it into account how distant the background subject is from the main subject. Accordingly, it is impossible to know a difference in unsharpness of the background subject image in the final picture between a case where the background subject is distant from the main subject and another case where it is near the main subject. Therefore, it is quite difficult, if not impossible, to visually predict the unsharpness of the background subject image relative to the main subject image, that is, to what degree the main subject image stands out of the background subject image in the final picture.
In addition, the above publication does not mention how the visual effects can be displayed in relation to a set exposure mode in the case where the camera is provided with a plurality of exposure modes, and a desired exposure mode is selected out of those.
Neither does the above publication disclose a construction in which an action level of a main subject image in the final picture, i.e., how active or how still the main subject image will look in the final picture, is predictively displayed based on a moving speed of the main subject. Unexamined Japanese Patent Publication No. 2-126251 discloses a camera capable of detecting a camera shaking speed on an operator's side, determining a camera shake amount based on the detected camera shaking speed, and displaying the determined camera shake amount with the use of bars. However, this camera does not take actual movement of a main subject into account. Neither does this camera mention visual effects in the final picture, i.e., to what degree the main subject image looks active in the final picture, relative to the same movement of the main subject. Moreover, this camera is in no relation to a camera which displays the level of the visual effects in accordance with a selected exposure mode. Similarly to the former publication, the latter publication does not mention the relationship between the display of the level of the visual effects and exposure mode.